Apparatus for making filter means

ABSTRACT

A method and apparatus for making filter means of a type which is constructed to provide elongated, high surface area, cavities defined on opposite sides of a relatively thin wall formed of filtering material with only the ends of the filter means contacting an overwrapping outer tube thereby presenting maximum available surface area of the material from which the products are formed to the smoke for filtration is disclosed. A tow of suitable filtering material is passed through an air nozzle containing a mandrel centered therein, the tow thereby achieving a uniformly random, but tubular, configuration and then through a steam curing station followed by an air curing station. The formed rod is then again steam cured and passed to a crimping device which imparts a particular configuration thereto. The crimped rod is then again air cured, wrapped, and cut for embodiment, an addition material may choose either of a printing applicator device or a nozzle device.

Nov. 21, 1972 R. M. BERGER ETAL 3,703,429

APPARATUS FOR MAKING FILTER MEANS Original Filed June 10, 1970 6Sheets-Sheet 1 m N N (\J N C q E N a a u l 9 t v rv \S INVENTORS RICHARDM. BERGER ELWIN w. BROOKS.

b-mtg! ATTO RNE Y Nov. 21, v1972 R. M. BERGER H APPARATUS FOR MAKINGFILTER MEANS 6 Sheets-Sheet 2 Original Filed June 10, 1970 uvmvronsRICHARD M. BERGER ELWIN w. BROOKS ATTORNEY 97 R. M. BERGER L APPARATUSFOR MAKING FILTER MEANS Original Filed June 10, 1970 6 SheetsSheet 3FIG. 10

INVENTORS RICHARD M. BERGER ELWIN W BROOKS JAM ATTORNEY R. M. BERGERETAL 3,703,429

APPARATUS FOR MAKING FILTER MEANS Original Filed June 10, 1970 Nov. 21,1972 6 Sheets-Sheet FIG. 15

IOO

FIG. 14

INVENTORS RICHARD M. BERGER ELWIN W BROOKS ATTORNEY Nov. 21, 1972 R. M.BERGER ETAL 3,703,429

APPARATUS FOR MAKING FILTER MEANS OriginalFiled June 10, 1970 6Sheets-Sheet 5 INVENTORS RICHARD M. BERGER ELWIN W BROOKS ATTORNEY NOV.21, 1972 BERGER ErAL 3,703,429

APPARATUS FOR MAKING FILTER MEANS I Original Filed June 10, 1970 6Sheets-Sheet 6 INVENTORS RICHARD M. BERGER ELWIN W BROOKS ATTORNEYUnited States Patent Int. Cl. D04h 1/44; B65h 5/22 US. Cl. 156-441 12Claims ABSTRACT OF THE DISCLOSURE A method and apparatus for makingfilter means of a type which is constructed to provide elongated, highsurface area, cavities defined on opposite sides of a relatively thinwall formed of filtering material with only the ends of the filter meanscontacting an overwrapped outer tube thereby presenting maximumavailable surface area of the material from which the products areformed to the smoke for filtration is disclosed. A tow of a suitablefiltering material is passed through an air nozzle containing a mandrelcentered therein, the tow thereby achieving a uniformly random, buttubular, configuration and then through a steam curing station followedby an air curing station. The formed rod is then again steam cured andpasses to a crimping device which imparts a particular configurationthereto. The crimped rod is then again air cured, wrapped, and cut. Inanother embodiment, an addition material may be added by means either ofa printing applicator device or a pulsating nozzle device.

This application is a divisional application of copending applicationSer. No. 45,109 filed June 10, 1970 now Pat. No. 3,637,447 which is acontinuation-in-part of co-pending application Ser. No. 727,477, filedMay 8, 1968 now Pat. No. 3,533,416, and of co-pending application Ser.No. 820,355, filed Apr. 30, 1969 now US. Pat. No. 3,599,646, which inturn is a continuation-in-part of the aforementioned application Ser.No. 727,477.

This invention relates to the production of filter means andparticularly to the production of tobacco smoke filter elements. Morespecifically, this invention relates to methods and apparatus for theproduction of such filter means.

Various prior art techniques are known for making filters for use inconnection with cigarettes, and the like, although the resultingproducts, in general, have one or more disadvantages. Perhaps the mostimportant property of a filter means is its efiiciency, that is, itsability to remove undesirable constituents from tobacco smoke.Filtration efiiciency is ordinarily measured in terms of the percentageof total particulate matter (TPM) removed from the smoke, although thereis also some concern for the percentage of gas phase constituents whicha filter means is capable of removing. While filtration etficiency isperhaps the most important property of a cigarette filter means, it hasbeen necessary, with prior art filter devices, to compromise thefiltration efficiency in order to provide this filter with otherproperties, such as pressure drop, taste, hardness, appearance and cost,which are important from the standpoint of acceptability. For example,the most commonly utilized cellulose acetate filter means has arelatively low filtration efficiency since increased efficiency can onlybe obtained either by increasing the density of the filter material orthe length of the filter element, both of See which produce a pressuredrop across the filter which is excessive and unacceptable from acommercial standpoint. While various suggestions have been made for theproduction of filter means which have improved filtering properties,such prior art developments have not become commercial either becausethe resultant filter means have been found to have objectionable tastecharacteristics whereby cigarettes provided with such filtering meansfail to satisfy a large segment of the smoking public or because thetechniques and/or the materials utilized in the production of suchfilter means have increased the cost excessively.

In any event, it is well known in the industry that there is no filtermeans presently on the market which provides relatively high filtrationefficiency, on the order of 60-95 percent (TPM), without suffering fromundesirably high manufacturing costs, poor taste, high pressure drop orother such commercially unacceptable characteristics. The need anddesirability of providing; such a filter means is believed to be readilyapparent, and the invention described and claimed in the aforementionedco-pending application Ser. No. 727,477, is directed to this need. Thatinvention provides a filter means for use with a cigarette, or the like,having exceptionally high filtration efiiciency, in many embodimentsremoving as much as percent of the total particulate matter, whilehaving an acceptable pressure drop, as well as satisfactory taste,"hardness and appearance. Further, there is described in the aforesaidco-pending application Ser. No. 727,477 various techniques for theproduction of a filter means of the type described utilizing inexpensivematerials in relatively small quantities, as well as simple andefiicient procedures whereby such filter means can be manufactured on amass production basis at a cost which is acceptable to the industry.Accordingly, the present invention provides processing equipment andtechniques which permit high speed, continuous production of integralproducts of this nature without the use for handling special bafiles orother extraneous elements which tend to slow down production rates andincrease rejects due to the difliculty in manipulating such smallarticles in a commercial operation.

A particular means for forming filter elements of the type described isdescribed on pages 13 through 15 of the aforementioned co-pendingapplication Ser. No. 727,477 and such disclosure is embodied herein inits entirety by reference. The aforesaid means, described in relativelygeneral terms in the aforementioned co-pending application, is the basicmeans utilized for manufacturing the novel filter of that invention. Thepresent invention, however, is concerned with a more efiicient improvedapparatus for achieving the result, namely, the production of that novelfilter.

Accordingly, it is a primary object of the present invention to providean apparatus for making filters of the type described which operates athigh speed.

It is another primary object of the present invention to provide anapparatus for the high speed, continuous production of filters of thetype described without the need for handling special bafiles, or otherextraneous elements.

It is a further object of the present invention to provide an apparatusfor making filters of the type described using a large variety offiltering materials.

Consistent with the foregoing objects, it is yet another object of thepresent invention to provide an apparatus for the manufacture of filtermeans which are self-sustaining and self-centering, with an integralconstruction, and with a maximum available surface area being presentedfor filtration of smoke passing therethrough.

It is still another object of the present invention to provide animproved filter having high filtration efliciency while having anacceptable pressure drop.

It is yet another object of the present invention to provide an improvedfilter manufactured by the method and apparatus described.

Other objects of the present invention will either be set forthspecifically hereinafter or will be obvious from the following detaileddescription. Such description makes reference to the annexed drawings,wherein:

FIG. 1 is a schematic view of one embedomient of a method and means formaking filter elements of the type described;

FIG. 2 is an exploded vertical cross sectional view of means for forminga band of filtering material into an axially elongated, hollow,filtering element;

FIG. 3 is a side view of a mandrel used in conjunction with the means ofFIG. 2;

FIG. 4 is a perspective view of the mandrel support utilized inconjunction with the mandrel of FIG. 3 and the means of FIG. 2;

FIG. 5 is a perspective view of the air nozzle and mandrel assemblycontaining the elements depicted in FIGS. 2 through 4;

FIG. 6 is an enlarged fragmentary perspective view of a portion of afiltered cigarette incorporating a filter element manufactured accordingto the instant inventive concepts, parts being broken away and insection for illustrative clarity, and modifications of this embodimentof a filter means according hereto being shown in dotted lines;

FIGS. 7, 8 and 9 are enlarged fragmentary perspective views of otherembodiments of the filter of FIG. 6;

FIG. 10 is a partially broken away vertical elevational view of thecrimping assembly utilized in the apparatus of the present invention andembodying the crimping wheel of FIG. 11;

FIG. 11 is a vertical elevational view of a crimping wheel used in theapparatus of the present invention;

FIG. 12 is a partial edge view of the crimping wheel of FIG. 11;

FIG. 13 is a vertical sectional view, taken on line 13-13 of FIG. 12;

FIG. 14 is a side View, partially broken away, of a filter rod made inthe apparatus of the present invention;

FIG. 15 is a transverse cross sectional view, taken along line 15-15 ofFIG. 14;

FIG. 16 is a transverse cross sectional view, taken along line 16-16 ofFIG. 14;

FIG. 17 is a fragmentary schematic view of another embodiment of themethod and means of the present invention;

FIG. 18 is a fragmentary schematic view of still another embodiment ofthe method and means of the present invention; and

FIG. 19 is a fragmentary schematic view of yet another embodiment of themethod and means of the present invention.

Like reference characters refer to like parts throughout the severalviews of the drawings.

Referring now to the drawings, and more particularly to FIG. 1, a methodand means for forming filter elements of the type described isschematically designated by the reference numeral 10. It should be notedat the outset that the various stations of the apparatus are arranged ina single plane, but for ease of illustration, the schematic presentationis shown in two segments. Filtering material in sheet form is designatedat 12. This filtering material in band form is coming from a bale andband forming apparatus conventional in the trade which are not shown.The filtering material 12 can comprise any suitable substance, such as,for example, cellulose acetate fibers in the form of a continuousfilamentary tow. For certain uses and to achieve certain filtering and/or adsorbing and/or liquid-holding properties, the cellulose acetatefibers may be mixed with other materials, such as, cellulose, viscose,cotton, cellulose acetate-butyrate, cellulose propionate, activatedcarbon, asbestos,

glass fibers, metal fibers, wood fibers, and the like. The material ispreferably opened, crimped, continuous filamentary cellulose acetate towhaving about 9 percent glycerin triacetate as a plasticizer in finedroplets distributed upon its surface. Any suitable plasticizer may beused, such materials being well known in the art.

The term continuous filamentary tow, as used in this specification andthe appended claims, is intended to define a material such as that whichresults when filaments extruded from a plurality of spinnerets arebrought together and combined to form a continuous body of iibersrandomly oriented primarily in a longitudinal direction. In such a tow,the filaments are generally longitudinally aligned in substantiallyparallel orientation, but include crimped portions which may form shortsections running more or less at random in non-parallel diverging andconverging directions.

Continuous filamentary tows of plasticized cellulose acetate fibers aswell as various other plastic materials, such as polyethylene,polypropylene, nylon and the like, have been used heretofore in themanufacture of smoke filters for cigarettes, cigars, and the like.Although the process of this invention is applicable to the variousfilamentary materials of this type, since plasticized cellulose acetateis the most common plastic used in the manufacture of cigarette filters,the specification hereof will be generally set forth in terms of thismaterial. However, it is to be understood that the instant inventiveconcepts are not to be limited to this preferred embodiment.

Generally, the fibers of a cellulose acetate tow merging from thespinneret are bunched together to form a raw tow" which is collectedinto a bale for subsequent processing. Such processing usually involves,in addition to unwinding of the raw tow, spreading apart of the fibersto provide a relatively thin layer of the same, tensioning of the fibersto render the crimp of uniform character, and impregnating the fibrouslayer with plasticizer to bind adjacent fibers together.

The tow of filtering material 12 in band form is fed into a stuffer jet,or air nozzle, 14. The construction of the air nozzle 14- is shown inFIGS. 2 through 5. The air nozzle 14 comprises an outer member 16, aninner member 18, a mandrel 20, a mandrel support 22, and a retainingring 24. The air nozzle '14 is generally shaped as a truncated cone,thereby having a greater cross-section at the entrance end 26 than atthe exit end 28. The inner member 18 is suitably connected to the outermember 16 as, for example, by the threaded portions 30 and 32. By use ofthreaded portions 30 and 32, the alignment of inner member 18 in outermember 16 can be adjusted for a purpose which will become apparent. Theinner member 18 is also threaded at 34 and mandrel support 22 isthreaded at 36. Retaining ring 24 contains threaded portion 38 tocooperate with the threads 34 and 36 thereby holding mandrel support 22in position. The mandrel support 22 has an inner portion 42 in annularrelation with the outer portion thereof 44. Inner portion 42 of mandrelsupport 22 is supported by support portion 46. Inner portion 42 issuitably threaded at 48 to receive threaded portion 40 of mandrel 20.

Outer member 16 has a connection 50 for compressed air. Wall 52 of outermember 16 and wall 5-4 of inner member 18 are of such a relationshipthat, when assembled, annular space 56, as best seen in FIG. 1, iscreated. The purpose of annular chamber 56 will become apparent from thefollowing description.

Returning now to FIG. 1, it will be seen that the elongated band offiltering material 12 enters the rearward end 26 of air nozzle 14passing through the mandrel support 22 and generally being forced, in arandom manner, around inner portion 42 of the mandrel support 22. Thetow at this point is generally a hollow tubular element which continuesaround mandrel 20 to the forward end 28 of air nozzle 14. As the towemerges from the forward end 28 of air nozzle 14, it is mixed with airsupplied through fitting 50 and passing through chamber 56 to the exit,or forward, end 28 of air nozzle 14. Adjustment of inner member '18 inouter member -16 by means of threaded portions '30 and 32 creates a venturi-like opening at the exit end 28 of air nozzle 14, between forwardend 19 of inner member 18 and forward end portion 21 of outer member 16.This opening could range in size from fully closed to about inch, butthe practical limits of use, in order to obtain the desired venturieffect at customary air pressures, are from about 0.005 to about 0.050inch. The tow emerging from the exit end 28 of air nozzle. 14, mixedwith air, explodes or blooms into a uniformly random fluify mass 58before passing into the first curing station 60. Mandrel 20 passesthrough air nozzle 14 and into the first curing station 60, extendingthrough and slightly beyond first curing station 60. It should be notedat this point, that the upstanding portion 46 of mandrel support 22 doesnot affect the ultimate tubular shape imparted to the tow since the towcomprises a plurality of plasticized random filaments which separatewhen going around that obstruction but then come together and, inpassing through the air nozzle 14, assume the proper cross-section.

The first curing station 60 is a heating and shaping apparatus, such asthat disclosed in US. Pat. No. 3,095,343, issued on June 25, 1963 toRichard M. Berger. Since this apparatus is now known in the art, it needonly be described herein in general terms, reference being had to theaforementioned US. Pat. No. 3,095,343 for details of its construction.

The heating and shaping apparatus making up the first curing station 60is constructed in such a way that the moving tow which is being formedinto a generally rod-like formation is contacted with steam as it passesthrough a die. The application of the steam to the filamentary tow as itis gathered together appears to result in softening of the tow fibersand the plasticizer carried thereon, and definitely has the efiect ofuniformly bonding the fibers of the tow together as they are gathered.By passing the steam onto the tow under pressure in a confined area atan angle to the longitudinal axis, and in a direction opposite thedirection of movement of the tow, the steam is caused to pass throughthe tow, between the fibers and past the fibers as they are beinggathered together. All of the filaments and all of the plasticizer arethus at least substantially uniformly heated, and bonding is at leastsubstantially uniform throughout. Thus, the steam-treating apparatus ofthe aforementioned US. Pat. No. 3,095,343 produces a tubular, rod-liketow which proceeds to further treatment. Using the apparatus of thepresent invention, however, with the forward end of the mandrel 20extending into and through the first curing station 60, the tow isconverted to an axially elongated, hollow element 62.

The cured tow emerging from the first curing station is generallyself-sustaining in shape and in cured condition. The term cured, as usedin the art, means a tow obtained from a process by which the fibers ofthe tow are bonded to adjacent fibers after the fibers have beengathered into a rod-like structure. The cured tow 62 then passes to asecond curing station 64 wherein dry air is passed on to the tow andthrough the tow to set the fiber components and plasticizer componentsof the tow so that it has complete dimensional stability without excessstiffness or fiber fusion. Preferably, the air which is passed on to thetow at the second curing station 64 is perfectly dry, has a temperatureof 90 degrees F. or below, and is maintained under a pressure of between15 and 100 p.s.i.g. Moreover, for optimum results, the air should bepassed onto the tow counter-current thereto and at an angle ofsubstantially 45 degrees to the longitudinal axis of the tow, in muchthe same way as the steam contacts the tow in the first curing station60. A suitable apparatus for air-treating the tow at the second curingstation 64 is described in detail in the aforementioned US. Pat. No.3,095,343. The air inlet to the second curing station 64 is indicated at66, while the steam inlet to the first curing station 60 is indicated at68.

After leaving the second curing station 64, the tow 62 passes to apulling device generally designated by the numeral 70. The pullingdevice 70 can be any conventional device for applying motive power tothe continuous filter rod 62 to move the same through the apparatus. Asdepicted in FIG. 1, the pulling device could be a conventional overwrapgarniture with an endless belt 72 imparting a pulling movement to thetow 62. The belt 72 is driven by drive means schematically shown as 74.

Before continuing with the description of the method and apparatus ofthe present invention, it would be helpful to become familiar with theconstruction and advantages of the inventive filter means described andclaimed in the aforementioned co-pending applications Ser. Nos. 727,477and 820,355. To this end, attention is directed to FIGS. 6 through 9,wherein a portion of a filter cigarette is designated generally by thereference numeral 76 and comprises basically a tobacco portion 78 and afilter portion 80. The tobacco portion 78 comprises a rod of tobacco 82overwrapped with paper, or the like, 84, as usual. The filter portion80, in the embodiment shown in FIG. 6, comprises one form of filterelement according to the invention of the aforementioned co-pendingapplication Ser. Nos. 727,477 and 820,355 designated generally by thereference numeral 86 and secured in endto-end relationsihp with one endof the tobacco portion 78 as by a tipping overwrap 88.

The filter element 86 includes basically an axially elongated, hollow,outer member 90 and an axially elongated, hollow, inner member 92disposed within the outer member 90. In this embodiment, the outermember 90 is shown as a cylinder of ordinary plug wrap as isconventionally used in the manufacture of filter elements forcigarettes, although this member may be formed of plastic or othermaterials, if desired.

The inner member 92 is that element with which we are primarilyconcerned in the steps thus far described in the method and apparatus ofthe instant invention. That is what may be called a tube formed primarlyof any one, or a combination of various, filtering media, as alreadydescribed hereinabove. One end portion 94 is cylindrical providingperipheral portions of the outer surface of the inner member 92, limitedin axial extent which are juxtaposed to portions of the inner surface ofthe outer member 90 to at least substantially preclude axial passage ofsmoke across the area therebetween. Any desired adhesive means (notshown) may be included in this area to provide a smoke-tight seal,although the outer member 90 may merely be overwrapped about the innermember 92 to provide a substantially smoke-tight seal in this area. Theimportant characteristic of this area is that smoke will pass throughportions of the filtering material of the inner member 92 as explainedhereinafter before bypassing the inner member across this area.

It will be noted that the major portions of the outer surface of theinner member 92 are spaced from the inner surface of the outer member 90to define first elongated, high surface area, cavity means 96therebetween, this cavity means including the area surrounding the endof the inner member 92 spaced from the sealed area at 98 particularly ifthis end of the inner member is spaced inwardly (not shown) from thecorresponding end of the outer member 90.

First integral portions 100 of the inner member 92 define a first areawhich extends across the interior of the inner member 92 and whichoffers at least as much resistance to passage of smoke as the filteringmaterial from which the inner member 92 is primarily formed. These firstportions 100, in the embodiment of FIG. 6, are defined by the end of theinner member 92 remote from the sealed area at 94 being crimped andpreferably sealed in a manner to be described in more detailhereinafter. In this manner, the use of a separate baffie or closingelement is avoided. Basically, these first portions 100 precludepreferred entry of the smoke from the tabacco portion 78 into theinterior of the inner member 92 through this end of the inner member 92and insure that the smoke will pass more uniformly through the filteringmaterial of the inner member 92 from the first cavity means 96. As willbe seen in FIG. 6, the first portions 100 in that embodiment are crimpedto form a generally or Z-shaped cross-section, the laterally terminaledges 102 of which contact the inner surface of the outer member 90 toassist in centering the inner member 92 within the outer member 90 andin defining the first cavity means 96. In the preferred embodiment, onlythese laterally terminal edges 102 and the afore-mentioned peripheralportions 94 of the inner member 92 contact the outer member 90, theremainder of the outer surface of the inner member 92 being spaced fromthe inner surface of the outer member 90, thereby utilizing the maximumavailable surface area for filtration.

Alternative forms of crimping are shown in FIGS. 7, 8 and 9. The supportgiven to the outer member 90 by the Y-shaped or cruciform ribs shown inFIGS. 7 and 8 is better than that given by the simple S or Z crimp shownin FIG. 6. In FIG. 9, a further alternative form of inner member 92 isshown. In this embodiment, the walls of member 92 are crimped so as toleave ribs which are arranged helically around the longitudinal axis ofthe member 92. By this means, good support is given to the outer member90 and the cross-section of the latter may, when it is made of thinmaterials, be kept substantially circular.

Return to FIG. 6, second portions 98 of inner member 92 define a secondarea extending across the interior of the inner member 92 which olfersless resistance to passage of smoke than the sealed area at 94. Thesesecond portions 98 may merely be the inner surface of the end portion ofthe inner member 92 remote from the first portions 100 and the secondportions 98 define second elongated, high surface area, cavity means104. Thus, it will be seen that smoke passing through the filter elementbetween opposite ends thereof must travel through both the first cavitymeans 96 and the second cavity means 104 and must pass through thefiltering material from which the inner member 92 is primarily formed.This construction provides an extremely high surface area for contactbetween the filtering material and the smoke, on the order of seventimes or more than the surface area presented by the end portion of aconventional cellulose acetate filter. Yet, the construction of thisfilter, as will be readily recognized, provides substantially lesspressure drop than a conventional cellulose acetate filter means of thesame length. In this manner, extremely high filtration efiiciency willbe provided by the filter means without encountering any difiiculty withrespect to pressure drop.

Since the pressure drop of a filter means as hereinabove described isquite low, it is possible to secure a plug or disc 106 of celluloseacetate or any other desired material within the open end of the innermember 92, as shown in dotted lines in FIG. 6. This disc 196 then servesas the aforementioned second portions of the inner member 92 and may beincluded, if desired, to merely provide the filter element 86 with theappearance of a solid plug. Further, the disc 106 may be utilized toincrease the pressure drop of the filter means 86 with particular tastecharacteristics or to enhance the physical characteristics of thefiltering material from which the inner member 92 is primarily formed byfiltering out certain constituents of the smoke which would otherwisepass through the filter means 86. Finally, the disc 106 serves toprovide a second cavity means 104 having both ends closed whereby anadditional smoke-modifying material 108 may be retained in the secondcavity means 104. For example, this additional smoke-modifying material108 may be a quantity of loose sorbent material in particulate form suchas activated carbon, silica gel, or other adsorbents which enhances thevapor phase filtration efficiency of a filter means as hereinabovedescribed. It should be understood that this disc 106 is not necessaryto the filter and, in fact, is ordinarily not utilized since itnecessitates handling an additional element. However, for specialeffects, it may be included, if desired. Furthermore, the cavity 104 maybe closed by a plug 110 shown by dotted lines. Additionally, in thepreferred embodi ment shown in FIG. 7, an additional series of crimps orfurther integral peripheral portions 112 extending around a peripheralportion of the inner element 92 is provided. This insures the properpassage of the smoke through the filter.

Returning now to FIG. 1, when the tow, or tube 62 which will be used tomake the inner portion 92 of the filter, leaves the pulling device 70,it passes into a third curing station 114 which is a steam jet quitesimilar to that used in first curing station 60. Basically, theconstruction of the steam jet in third curing station 114 is the same asthat used in first curing station 60 with several minor modificationswhich will be apparent to one skilled in the art. Steam enters thirdcuring station 114 through inlet 116 and passes through and around thetow 62 as it moves through the steam jet. Unlike the first curingstation 60, however, the steam in third curing station 114 need notnecessarily run counter-flow t0 the tow, but may actually passco-currently with the same. In fact, in a preferred embodiment, thesteam runs with the tow rather than counter to the same in third curingstation 114. According to the concepts of the instant invention, thissecond steam treatment is an important preconditioning of the rod inorder to prepare the same for the crimping operation to be performed incrimping station 118. The crimping could be performed without thispreconditioning, but the amount of heat and pressure which would benecessary renders such a step less desirable. It has been found thatwhen the tow is preconditioned in third curing station 114, the crimpingcan be done extremely easily. The crimping station 118, of course, willimpart the desired configuration to the rod, as shown in FIGS. 6 through9.

For a further understanding of crimping means 118, attention is directedto FIG. 10 wherein crimping means 118 is shown in more detail inelevational view, looking at the device from the rear, or inlet end. Thehousing 120 is partially broken away for ease of illustration. Thepreconditioned rod 62 coming from the third curing station 114 enterscrimping means 118 at 122. In passing through crimping means 118, therod is intermittently contacted by crimping wheels 124. Crimping wheels124 are arranged in two pairs of opposed wheels. The crimping wheels124, which will be described more fully hereinbelow, are driven byconventional means, such as bevel gears 126 which are interconnected byshafts 128 which, in turn, are powered by an external power source (notshown) through drive means 130. The crimping wheels 124 are mounted,through the shafts 128, in heater blocks 132 which also act as bearingsupports. The heater blocks 132 carry a cartridge-type heater (notshown) and, accordingly, heat the crimping wheels 124.

As can be seen from FIGS. 11 through 13, crimping wheel 124 comprises aplurality of axially projecting first embossing portions 134circumferentially spaced around the periphery of the wheel. A pluralityof transverse grooves 136 are also arranged at spaced intervals aroundthe periphery of the wheel 124, alternating with the first embossingportions 134. Second embossing portions 138 extend circumferentiallyaround the periphery of the embossing Wheel 124 between first embossingportions 134 and transverse grooves 136. Second embossing portions 138include a pair of circumferential grooves, or valleys 139 and aplurality of raised portions, or lands, 141.

Keeping in mind the description of the filter means in FIGS. 6 and 7,and turning momentarily to FIGS. 14, and 16, it will be seen that thetow 140 emerging from crimping means 118 comprises acontinuous tubecrimped at spaced intervals in such a manner that when out apart, itwill provide a plurality of inner members 92 of filter elements 86.First integral portions 100 of the inner members 92 are produced by thefirst embossing surfaces 134 of the crimping wheels 124. The additionalseries of crimps 112 are produced by second embossing surfaces 138. Theperipheral unembossed areas 142 are the result of the transverse grooves136. Since the rod 62 is a hollow tube, the crimped rod 140 retains thehollow configuration in those areas which have not been compressedbycfimping means 118. This hollow configuration is shown in FIG. 16wherein the cavity 144 appears.

Returning once again to FIG. 1, the crimped rod 140 emerging fromcrimping means 118 passes to fourth curing station 146. Fourth curingstation 146 is an air jet similar to second curing station '64 havingair supplied thereto through connection 148. This final curing stagesets the crimped rod 140 into its final shape. The rod 140 of crimpedinner elements 92 is then overwrapped, for example, with a sheet ofordinary plug wrap, such as shown at 150, by-passing the crimped rod 140and the plug wrap 150 through a means 152 which is a conventionaloverwrap garni-ture, with the assistance of an endless belt 156. Theplug wrap 150 forms an axially elongated hollow outer element 90, thelateral edges of which may be secured together to form a longitudinalbutt seam, or a longitudinal lapped seam, as is well known, sealingmeans 158 being shown for this purpose.

The continuous rod 160 of overwrapped combined inner and outer elements90 and 92 may then be cut in any conventional manner, as by meansschematically shown at 162, to provide a plurality of segments 164. Forconvenience in handling, each segment 164 may initially include fourfilter elements, the segments being first further subdivided, as shownby the dotted lines 168 in FIG. 14 to provide segments including twofilter elements. The segments may then be associated with a pair oftobacco portions and overwrapped with a tipping paper before furthersubdividing the same to form two filtered cigarettes, each including asingle filter element of the type shown, for example, in FIG. 6.

The foregoing detailed description of the present invention is drawn tothe preferred embodiment thereof. In an alternate form of thatembodiment, there is provided a method and apparatus for making a filterof the type described, which filter further includes a section carryingan additional material capable of providing a required filtering orother effect upon tobacco smoke and unitary with a section without sucha material. This additional material capable of having a filtering orother required elfect upon tobacco smoke can be, prior to itsapplication to the above-described filter means, in particulate, liquidor suspended state. Accordingly, method and means are provided in analternate embodiment of the present invention for applying suchadditional material to the filter means. The additional material, asalready explained, can be any material capable of providing a requiredfiltering or other effect upon tobacco smoke, and is preferably finelydivided activated charcoal. A method and means of applying such amaterial is disclosed and claimed in US. Pat. No. 3,371,000, whichissued on Feb. 27, 1968. Reference is now had to FIGS. 17 and 18 whereinthe additional steps and apparatus according to one variation of thisembodiment are described. As the rod leaves the pulling 176 dips intothe slurry in the trough 180 at its lowest part and is in surfacecontact with the further fountain roll 178, which in turn is in surfacecontact with the applicator roller 172. The doctor roll 180 is sodisposed as to doctor, or meter, the amount of slurry carried round bythe roll 176 to be, ultimately, transferred to the ap plicator roller172. The applicator roller 172 comprises a plurality of surfaces 184separated from one another by axially directed valleys 186. The surfaces184 conform to an imaginary cylinder coaxial with the roller 172'. Eachsurface 184 may have an arcuate length equal to whatever length ofstripe of the additional material it is desired to print onto the filtermeans. Additionally, the surfaces 184 may be separated from one anotherby any desired arcuate length. The pressure roll 174 serves to press therod 62 into contact with the surfaces 184. The rod 62 passes into andthrough applicator device on endless belt 188 which is entrained abouttwo rollers 190 and 192. The rod 62 passes between the nip or roller 192and roller 194 as it enters onto endless belt 188.

In FIG. 18, applicator device 170 also comprises applicator roll 172,pressure roll 174, fountain roll 176, further fountain roll 178, doctorroll and trough 182. The endless belt and its accompanying drive rollersare not used in this embodiment, the rod 62 merely passing betweenapplicator roller 172 and pressure roll 174. In both FIGS. 17 and 18, itcan be seen that as the rod 62 leaves the applicator device 170, itpasses into third curing station 114 where it is again cured with steambefore entering crimping means 118. This curing additionally serves toset the stripe of activated carbon where it has been printed on the rod62. It is additionally apparent that the length of the printed stripe ofactivated carbon is determined by the size of the filter, the unprintedareas being those areas wherein the plurality of filters will be cutapart.

In another variation of this embodiment, the slurry of additionalmaterial, such as activated carbon, or finely divided additionalmaterial, such as activated carbon alone or in combination with asuitable resin, such as those disclosed in -U.S. Pat. No. 3,217,715,granted to Richard M. Berger on Nov. 16, 1965, or other additive, isapplied to the hollow inner portion 144 (as shown in FIG. 16) of the tow62 at the first curing station 60. This is done by providing a mandrel20a which is hollow, as indicated by the broken lines 196. The hollowmandrel 20a is fed, at its rear or inlet end, with the additionalmaterial from a reservoir 198. The additional material is ejected fromthe hollow mandrel 20a at its forward end, in the neigh borhood of firstcuring station 60, to deposit the additional material in the hollow tube62. The additional material is injected in this manner by means of apulsating feed to the mandrel. The mandrel 20a, in effect, serves as apulsating nozzle. The pulsating feed from reservoir 198 to hollowmandrel 20a is accomplished by known means which need not be hereindescribed.

It will, at this point, be apparent to one skilled in the art that thevarious steps in the apparatus of the present invention must becarefully coordinated to insure a properly made and uniform product. Forthis reason, the driving means of pulling device 70, crimping device118, and cutting device 162 are separately driven and synchronized usingknown synchronization means, or, preferably, driven by a single drivingmeans through a drive train, including belts, and pulleys, and gears, soas to insure perfect synchronization of all moving parts, so thatuniform manufacture will be achieved. Furthermore, in the embodiments ofFIGS. 17 and 18, the drive means thereof are also synchronized with theother stations of the apparatus. By the same token, in the embodiment ofFIG. 19, the pulsating feed of the additional material is so controlledand synchronized with the other stations of the inventive apparatus thatdeposit of the additional material is controlled in a proper manner.

Having now described the process and apparatus of the present inventionand having set forth various advantages thereof, it should be apparentthat the objects set forth at the outset of this specification have beensuccessfully achieved. While this invention has been described withreference to presently preferred exemplary embodiments thereof, itshould be clearly understood that the invention is not limited theretobut may be variously practiced within the scope of the following claims.

Accordingly, what is claimed is:

1. Apparatus for making a filter means comprising:

(a) means for forming and bonding a continuous filamentary tow filteringmaterial into an axially elongated, hollow, inner element;

(b) means for crimping said inner element at axially spaced locations toform closed crimped portions extending across the interior of said innerelement at said spaced locations with uncrimped portions therebetween;

(c) means for overwrapping said inner element with an axially elongatedhollow outer element, portions of the inner surface of which arejuxtaposed to peripheral portions of said uncrimped portions of saidinner element in a manner to substantially preclude axial passage ofsmoke across the area between said peripheral portions of said innerelement and said portions of the inner surface of said outer element,the major portion of the outer surface of said inner element beingspaced from the inner surface of said outer element; and

(d) means for cutting said elements to provide segments having at leastpart of one crimped portion of said inner element and at least part ofone uncrimped portion of said inner element.

2. The apparatus defined in claim 1, wherein said means for forming andbonding said filtering material into an axially elongated, hollow, innerelement comprises a substantially frusto-conical air nozzle means and anelongated mandrel axially disposed in said air nozzle.

3. The apparatus defined in claim 2, wherein said forming and bondingmeans further includes a first curing station, said first curing stationcomprising steam jet means, said mandrel extending from said air nozzlemeans into said steam jet means.

4. The apparatus defined in claim 2, wherein said air nozzle meansincludes an inner portion and an outer portion, said inner portion beingadjustably mounted within said outer portion to provide an annular spacebetween said inner portion and said outer portion, and air inlet meansto provide a flow of air to said annular space, said inner portion beingadjusted in said outer portion such that venturi means are provided atthe outlet end of said air nozzle means, whereby said filtering materialexits said air nozzle means with said flow of air,

air.

5. The apparatus defined in claim 4, wherein said air nozzle meansfurther includes mounting means for said mandrel and retaining means.

6. The apparatus defined in claim 2, wherein said forming and bondingmeans further includes a second curing station, said second curingstation comprising air jet means.

7. The apparatus defined in claim 1, wherein said crimping meanscomprises a plurality of heated crimping wheels and drive means for saidwheels, said crimping wheels including a plurality of circumferentiallyspaced, axially projecting first embossing portions, a plurality ofperipherally disposed circumferential second embossing portions, and aplurality of transverse grooves arranged at spaced intervals around theperiphery of said wheel.

8. The apparatus defined in claim 7, further including steam jet meansbefore said crimping means and air jet means immediately after saidcrimping means.

9. The apparatus defined in claim 1, further comprising means forproviding a second filtering material to said axially elongated, hollow,inner element.

10. The apparatus defined in claim 9, wherein the lastmentioned means isan applicator means which comprises an applicator roller for printing aslurry of said second material on said inner element, supply means forsaid slurry, fountain roll means for transferring said slurry to saidapplicator roller means, and pressure roll means to support said innerelement for application of said slurry thereto, said applicator meansbeing located before said crimping means.

11. The apparatus defined in claim 9, wherein the last-mentioned meanscomprises a pulsating nozzle means for selectively injecting said secondmaterial into the hollow portion of said inner element.

12. Apparatus for making a filter means comprising:

(a) means for forming filtering material into an axially elongated,hollow, inner element, said forming means comprising a substantiallyfrusto-conical air nozzle means, axially elongated mandrel means axiallydisposed in said air nozzle means, first curing station means includingsteam jet means, said mandrel extending from said air nozzle means intosaid steam jet means, and second curing station means including air jetmeans;

(b) third curing station means comprising steam jet means;

(c) means for crimping said inner element at axially spaced locations toform closed crimped portions extending across the interior of said innerelement at said spaced locations with uncrimped portions therebetween;said crimping means comprising a plurality of heated crimping wheels anddrive means for said crimping wheels, said crimping wheels including aplurality of circumferentially spaced, axially projecting, firstembossing portions, a plurality of peripherally disposed circumferentialsecond embossing portions, and a plurality of transverse groovesarranged at spaced intervals around the periphery of said wheels;

((1) fourth curing station means comprising air jet means;

(e) means for overwrapping said inner element with an axially elongatedhollow outer element, portions of the inner surface of which arejuxtaposed to peripheral portions of said uncrimped portions of saidinner element in a manner to substantially preclude axial passage ofsmoke across the area between said peripheral portions of said innerelement and said portions of the inner surface of said outer element,the major portion of the outer surface of said inner element beingspaced from the inner surface of said outer element; and

(f) means for cutting said elements to provide segments having at leastpart of one crimped portion of said inner element and at least part ofone uncrimped portion of said inner element.

References Cited UNITED STATES PATENTS 3,637,447 1/1972 Berger et al.156-480 3,095,343 6/1'972 Berger 156-180 3,297,512 1/1967 Cobb, Jr. etal. 156433 NORMAN G. TORCHIN, Primary Examiner A. T. SURO PICO,Assistant Examiner U.S. Cl. X.R. l56180

